Dispensing unit

ABSTRACT

The invention relates to a dispensing unit for dispensing two fluid substances. The dispensing unit comprises a pump assembly ( 2 ) having a first ( 4 ) and a second pump ( 5 ) which can be actuated by common, manually operable operating means ( 6 ) in order to simultaneously dispense the two fluid substances. The dispensing unit also comprises a reservoir assembly ( 3 ), the reservoir assembly comprising two reservoirs which are each provided at an outlet side with an outlet and are each delimited by a movable piston ( 13, 16 ) on the other side from the outlet, which pistons, during the dispensing of the fluid substances, move toward the respective outlets. According to a first aspect of the invention, the reservoir assembly ( 3 ) and the pump assembly ( 2 ) are separate assemblies which can be coupled to one another, in such a manner that in the uncoupled state each reservoir can be filled through the outlet of the reservoir, after which the pump assembly and the reservoir assembly are coupled to one another.

A first aspect of the present invention relates to a dispensing unit fordispensing two fluid substances in accordance with the preamble of claim1. The first aspect of the invention also relates to the reservoirassembly of a dispensing unit of this type.

WO 93/04940 has disclosed a dispensing device for simultaneouslydispensing two fluid substances.

This dispensing device has a first reservoir, which is delimited by aninner side of a first cylindrical tube, and a second reservoir, which isdelimited by the outer side of the first cylindrical tube and an innerside of a second cylindrical tube. The first and second tubes arearranged concentrically with respect to one another, the second tubesurrounding the first cylindrical tube. On the side remote from theoutlet side, the first reservoir is delimited by a continuous disk-likepiston and the second reservoir by an annular piston.

In the known dispensing unit, the two reservoirs are filled from theunderside, where the piston is located. Filling from the top is notpossible, since both the inlet valve and the outlet valve of the firstand second pumps do not allow the fluid substance to flow in theopposite direction. Therefore, the reservoir is filled at its still openunderside, after which the corresponding piston is moved into thereservoir which has been filled before. One drawback of positioning thepiston afterwards is that air is present between the fluid substance andthe piston in the reservoir.

This air which is present in a reservoir means that the volume which issubsequently dispensed by the pump in one pump stroke is not alwaysconstant. This is undesirable in particular in the case of dispensingunits which dispense two fluid substances in a defined volumetric ratio,since a slight difference in volume in the fluid substance dispensed cancause a considerable deviation in the intended volumetric ratio betweenthe two fluid substances dispensed. The latter problem occurs inparticular if the difference in volume between the first fluid substancedispensed during a pump stroke and the second fluid substance isconsiderable.

There are also known reservoir assemblies in which—after the filling viathe open underside—a piston provided with a closable opening is put inplace. Air can escape via this opening, after which the opening isclosed off. Closing off the opening in the piston then requiresadditional operations to be carried out during the filling of thereservoir assembly.

In general, therefore, it is not easy to fill the known reservoirs ofthe abovementioned type and it is difficult to prevent air from beingpresent between the piston and the fluid substance.

The object of the first aspect of the invention is to create an improveddispensing unit for dispensing two fluid substances.

The object is achieved with a dispensing unit in accordance with thepreamble of claim 1 which is characterized in that the reservoirassembly and the pump assembly are separate assemblies which can becoupled to one another, in such a manner that in the uncoupled stateeach reservoir can be filled through the outlet of the reservoir, afterwhich the pump assembly and the reservoir assembly are coupled to oneanother.

As a result of the reservoirs of the reservoir assembly being filledthrough the outlets, there is no need to form an opening in thereservoirs which has to be closed up again after the filling operation,i.e. there is no need either to put the piston in place after thefilling operation or to close up an opening in the piston. This makes iteasier to fill a reservoir assembly according to the first aspect of theinvention with the first and second fluid substances in the first andsecond reservoirs, respectively.

Another advantage is that with the reservoir assembly according to thefirst aspect of the invention, it is possible to prevent air from beingtrapped between the pistons and the fluid substances introduced into thereservoirs.

For the reservoir to be filled, it is preferable for each piston to belocated in a piston filling position in the vicinity of the outlet. Thishas the advantage that there will be little or scarcely any air in thereservoir prior to the filling operation. This means that there is evenless risk of air remaining inside the filled reservoir. This doesrequire the piston to be able to move in opposite directions, i.e.towards the outlet and away from the outlet. During the fillingoperation, the piston then moves from the filling position in thevicinity of the outlet toward the piston position associated with acompletely filled reservoir. The risk of air being present in the filledreservoir can be reduced even further by at least partially sucking theair out of the reservoirs using a vacuum pump or the like prior to thefilling operation. This is possible in particular if, during the fillingoperation, a filling unit which has a filling head which can be placedon the reservoir assembly and which is connected to a vacuum pump ofthis type is used.

The diameter or cross section of the first and/or second reservoiradvantageously decreases in the direction of the outlet side over atleast a section of the length of the reservoir.

It is preferable for the pistons for a dispensing unit in accordancewith the first aspect of the invention to be made from a plastic whichis sufficiently resilient to enable the piston to bear in a sealedmanner against the walls of the reservoir in question. One drawback of aplastic material of this nature is that it experiences relaxation overthe course of time. This will reduce the resilience, with the resultthat the seal against the walls will also deteriorate. As a result ofthe width of the first and/or second reservoir being made to decrease inthe direction of the outlet side, the piston will, as it were, be pulledincreasingly more firmly into the cylindrical tube. This compensates forany reduced sealing action of the piston caused by the drop inresilience of the material of which it is made, with the result that aleak-free piston can be ensured during use of the dispensing unit.

However, one consequence of a decreasing reservoir width in thedirection of the outlet side would be that the further the piston movestowards the outlet, the greater the prestress which is applied to thepiston. In particular in the abovementioned piston position in thevicinity of the outlet, the prestress will then be relatively high. Thishas the drawback that this prestress will cause the relaxation in theplastic material of the piston to occur more quickly. This isparticularly disadvantageous when the piston is located in the vicinityof the outlet prior to the filling operation, since reservoir assembliesof this type are generally stored for a certain time after productionbefore being filled.

Relaxation can however also occur if the diameter or cross section ofthe reservoir in question is designed to be constant over the length ofthe reservoir, since the piston which is already present in thereservoir is generally under a certain prestress therein.

Consequently, it is preferable for the diameter or cross section of thereservoir to be increased over part of the length of the reservoir atthe abovementioned filling position in the vicinity of the outlet, insuch a manner that the piston is under reduced prestress in theabovementioned filling position in the vicinity of the outlet. Designingthe diameter or cross section of the reservoir in this way prevents theabovementioned rapid relaxation of the plastic piston material in thepiston located in the vicinity of the outlet. Consequently, as yetunfilled reservoir assemblies can be stored for a prolonged period oftime with the pistons in the filling positions in the vicinity of theoutlet.

However, one drawback of this is that while the dispensing unit is beingused, involving the reservoir in question being emptied, the piston canstart to leak when it reaches the vicinity of the outlet. However, sincethe reservoir is then virtually empty, the latter drawback does notpresent a major problem in practice.

It should be noted that if the pistons, prior to the filling of thereservoir in question, are in a different filling position, inparticular in the position furthest away from the outlet, it isadvantageous for the diameter or cross section of the reservoir toincrease at the piston position in which the piston is located prior tothe filling of the reservoir in question, so that the piston is under areduced prestress in this filling position.

The first aspect of the invention also relates to a reservoir assemblywhich is clearly intended for a dispensing unit in accordance with thefirst aspect of the invention and to a method for filling an assembly ofthis type. The first aspect of the invention also relates to a fillinghead for filling a reservoir assembly in accordance with the firstaspect of the invention.

A second aspect of the invention relates to a dispensing unit fordispensing a first and a second fluid substance in a defined(volumetric) ratio, comprising:

-   -   a first and a second reservoir for a stock of the first and        second fluid substances, respectively,    -   a pump assembly which comprises a first and a second pump, which        each have a pump chamber with a defined operative volume, and a        common, manually operable operating member for actuating the        first and second pumps.

WO 93/04940 has disclosed a dispensing unit for dispensing a first and asecond fluid substance, which dispensing unit comprises a pump assemblyhaving a first pump and a second pump for pumping the first and secondfluid substances and a manually operable operating member which can beused to actuate the pump assembly. The pumps are arranged concentricallywith respect to one another.

The first and second pumps of the known dispensing unit each comprise apiston and a cylinder which together delimit a pump chamber. Each pumpchamber has an inlet for sucking fluid substance out of the respectivereservoir and an outlet for dispensing a fluid substance through anoutlet passage to a dispensing opening.

A pump assembly of this type is designed to dispense a defined quantityof the two fluid substances in a predetermined volumetric ratio eachtime the operating member is operated. For the known unit, thisvolumetric ratio may be between 1:1 and 1:9. In this case, it isnecessary to create a specific dispensing unit of suitable dimensionsfor each individual volumetric ratio. It may be desirable to match thedispensing unit to a desired volumetric ratio, in particular in the caseof fluid substances which can be used in a plurality of ratios to givedifferent effects. In the case of the known dispensing unit, for eachvolumetric ratio this requires all the separate components of the pumpassembly to have specific dimensions which differ from a pump assemblyfor another volumetric ratio. This leads to logistical drawbacksrelating to the storage and production of these separate componentswhich differ for dispensing units for different volumetric ratios.

The object of the second aspect of the invention is to provide adispensing unit in accordance with the preamble of claim 27, with whichit is possible to easily match the dispensing device to a desired pumpdelivery of and/or volumetric ratio between the two fluid substanceswhich are to be dispensed by the dispensing unit when a pump isactuated.

The object is achieved by a dispensing unit in accordance with thepreamble of claim 27 which is characterized in that the pump assemblycomprises one or more exchangeable pump elements which form at least asection of the first and/or second pump. By selection of one or moresuitable exchangeable pump elements and by fitting them in the pumpassembly, it is possible to adapt the operative volume of the pumpchamber of the first and/or second pump.

The creation of a pump assembly with one or more separate exchangeablepump elements makes it easy to change the operative volume of the pumpchamber, i.e. the quantity of fluid substance dispensed by the pump inthe event of the latter being operated, for one or both pumps bysuitable selection of the one or more exchangeable pump elements. Byadapting one or both volumes which are dispensed by the pumps each timethe pump is operated, it is also possible to adapt the volumetric ratiobetween the fluid substances dispensed in one pump stroke as required.It is then no longer necessary for all the components of the pumpassembly to be specifically dimensioned for each volumetric ratio anddelivery.

Consequently, there is no need to keep a separate stock of componentsfor each desired volumetric ratio between the fluid substances which areto be dispensed, with the exception of the exchangeable pump elements.

In this context, it should be noted that in general the dispensing unitsare put together in such a manner that, after assembly by the producer,they will be difficult or impossible to dismantle. Moreover, they aregenerally disposed of after use. In this context, the word“exchangeable” should be read as indicating a choice which will be madeduring assembly. Subsequent replacement of the exchangeable pumpelements will generally only be possible in specific designs. Therefore,the second aspect of the invention provides benefits in particular withregard to production and logistics, since less specifically dimensionedcomponents will be required for dispensing devices with differentvolumetric ratios.

Although the retrospective exchange of the exchangeable pump elementswill generally take place less frequently, this possibility is not ruledout by the second aspect of the invention.

The pump assembly advantageously comprises a base part with a holdingsection for holding at least one of the exchangeable pump elements, theholding section preferably being designed to centre and/or position theexchangeable pump element which is held therein. With a base part ofthis type, it is easy to place the respective exchangeable pump elementinto the pump assembly in the correct way.

In one embodiment, the pump assembly comprises a first exchangeable pumpelement which is both held in the base part and coupled to the operatingmember. Since the operating member and the base part move with respectto one another when the pumps are operated, in this embodiment it isnecessary to provide a flexible exchangeable pump element or anexchangeable pump element which comprises at least two components whichcan move with respect to one another.

In one embodiment, the first and/or second pump is a bellows pump, thefirst exchangeable pump element at least in part forming a bellows pumpchamber. With an embodiment of this type, it is easy to match the volumedispensed by the pump in question in one pump stroke.

In another embodiment, the pump assembly comprises a first and a secondexchangeable pump element, the first exchangeable pump element beingcoupled to the operating member and the second exchangeable pump elementbeing held in the base part. In this embodiment, two components whichcan move with respect to one another when the pumps are operated arecreated exchangeably. This has the advantage that the exchangeable pumpelement does not have to be coupled both to the operating member and tothe base part. This is because having to do so can constitute anassembly drawback, certainly in view of the flexibility/movability whichis then required of the exchangeable pump element.

In a further embodiment, the first and/or second pump is a piston pump,the first exchangeable pump element forming the piston of the first orsecond pump, respectively, and the second exchangeable pump elementforming the cylinder of the first or second pump, respectively. By usinga piston pump, it is possible to accurately dispense a defined volume.This is advantageous in particular if the volumetric ratio between thevolumes dispensed by the-two pumps is high. A slight deviation in thevolume of a fluid substance dispensed when a pump is operated can thenlead to a considerable deviation from the desired volumetric ratio.

In a preferred embodiment, each pump is a piston pump, and the firstexchangeable pump element forms both pistons and the second exchangeablepump element forms both cylinders. In this embodiment, in each case onlytwo components are required to adapt the operative volumes of the pumpchambers of the two pumps. With a dispensing device of this type, it ispossible to produce a considerable range of volumetric ratios, forexample from 1:1 to 1:25.

The pump assembly is advantageously releasably coupled to the firstand/or second reservoir preferably via the base part of the pumpassembly. It is then possible, for example, to replace an emptyreservoir with a new, full reservoir. If the pump assembly is formedintegrally with one or both reservoirs, it is possible for the base partto be integrated with the top side of one or both reservoirs.

It is preferable for the first and second reservoirs to be of the“airless” type, i.e. for the fluid substance dispensed not to bereplaced in the reservoir by air, but rather for the volume of thereservoir to be reduced as the volume of the fluid substance dispensedincreases. This is possible, for example, by designing the reservoir asa flexible pouch which becomes smaller as the fluid substance isdispensed. The “airless” reservoir is preferably a cylindrical wall inwhich there is a piston which, during the dispensing of the fluidsubstance, is drawn towards the outlet of the reservoir, so that thevolume of the reservoir is thereby reduced.

With airless-type reservoirs of this type, it is possible to dispense avery accurate quantity by means of a pump of the pump assembly, sincethis quantity is not affected or is scarcely affected by the airpressure prevailing in the reservoir.

The one or more exchangeable pump elements according to the secondaspect of the invention can also be used in a dispensing device in whichonly one fluid substance is pumped. The exchangeable pump elements arethen used only to adapt the operative volume of the pump chamber of thepump in order to adjust the quantity of fluid substance dispensed by thedispensing unit in the event of a pump being operated as desired. Thevarious embodiments of the exchangeable pump element and the associatedpumps which have been discussed above in connection with two pumps canthen be applied in a corresponding way to the single pump of thedispensing unit for pumping one fluid substance.

A dispensing unit of this type for dispensing one fluid substance isdescribed in claims 27-49. The second aspect of the invention alsorelates to a pump assembly which is clearly intended for a dispensingunit in accordance with claim 50 and to a method in accordance withclaim 51.

It will be clear to the person skilled in the art that it is possible tocombine one or more of the measures of the first and second aspects ofthe invention in a dispensing unit. Such a combination of one or moremeasures of the first aspect of the invention with one or more measuresof the second aspect of the invention is deemed to be covered by thescope of protection.

Further advantages and characteristics of the first and second aspectsof the invention will be explained below with reference to a preferredembodiment shown in the drawing, in which:

FIG. 1 shows a cross section through a separate reservoir assembly inaccordance with the first aspect of the invention, and

FIG. 2 shows a perspective view of a cross section through a dispensingunit in accordance with the first aspect of the invention, in whichreservoir assembly and pump assembly are coupled to one another.

FIG. 3 shows a cross section through a dispensing unit in accordancewith the second aspect of the invention,

FIG. 4 shows a perspective view of a cross section through the pumpassembly of the dispensing unit shown in FIG. 3, and

FIG. 5 shows a perspective view of the pump assembly as shown in FIG. 4,and

FIG. 6 shows a perspective view of a cross section through the uncoupledreservoir section of the dispensing unit shown in FIG. 3.

FIG. 2 shows a dispensing unit for simultaneously dispensing two fluidsubstances, denoted overall by reference numeral 1. The dispensing unit1 is suitable for holding in the hand and comprises a pump assembly 2and a reservoir assembly 3. The pump assembly 2 and the reservoirassembly 3 are assemblies which are separate but can be coupled to oneanother and in this figure are shown coupled to one another. Thereservoir assembly 3 is shown separately in FIG. 1.

The pump assembly 2 of the dispensing unit 1 comprises a first pump 4and a second pump 5, and also an operating member which is designed asan operating button 6. By operation of the operating button 6, the firstand second pumps 4, 5 are actuated, with the fluid substances beingdispensed simultaneously through dispensing openings 7 a, 7 b. The pumps4, 5 shown are piston pumps. It is also possible to provide pumps of adifferent type, for example bellows pumps, instead of piston pumps.

If appropriate, the pump 4 and/or the pump 5 may be a foam-forming(piston) pump with a pump section for the fluid substance and a pumpsection for sucking in air, which air is mixed with the fluid substance,so that the latter is dispensed as a foam.

The reservoir assembly 3 comprises a first reservoir 8 and a secondreservoir 9. The two reservoirs 8, 9 are of the so-called “airless”type, in which the space which is formed by the dispensing of the fluidsubstances in the reservoir is absorbed by a decrease in size of thereservoir in question, in the present case by means of a piston whichcan move inside the reservoir.

The first reservoir 8 is delimited by an inner side of a firstcylindrical tube 10. The first cylindrical tube 10 is closed off on anoutlet side which is common to the first and second reservoirs 8, 9 by acover 11 in which there is a first outlet 12. That end of the firstreservoir 8 which is remote from the outlet 12 is delimited by amovable, continuous, substantially disk-like piston 13.

The second reservoir 9 is delimited by the outer side of the firstcylindrical tube 10 and an inner side of a second cylindrical tube 14.The first and second cylindrical tubes 10, 14 are arrangedconcentrically with respect to one another, the second cylindrical tube14 surrounding the first cylindrical tube 10.

The second cylindrical tube 14 is also closed off by the cover 11 at thecommon outlet side. An outlet 15 is provided in the annular section ofthe cover 11 which closes off the second reservoir 9, i.e. between thefirst and second cylindrical tubes 10 and 14, respectively. On that sideof the second reservoir 9 which is remote from the outlet 15, the secondreservoir is delimited by a movable, continuous, substantially annularpiston 16.

FIG. 1 shows the two pistons 13, 16 in a first filling position in thevicinity of the outlets, in which the two reservoirs 8, 9 of thereservoir assembly 3 have not yet been filled. The cover 11 of thereservoir assembly 3 is suitable for receiving a filling head of afilling unit, which filling head is designed to fill the reservoirs 8, 9through the outlets 12, 15. During the filling, the pistons 13, 16 willmove away from the outlet side towards a second piston position, inwhich, during use of the dispensing unit, the pistons are locatedfurthest from the outlet side.

After the filling operation, the pump assembly 2 is coupled to thereservoir assembly 2. The cover 11 is provided with a coupling rim 22for this purpose. Furthermore, the pump assembly 2 has connection pieces25, 26 on the underside, for the pumps 4, 5 which respectively fit intothe outlets 12, 15. In this case, the suction valves 27, 28 of the pumps4, 5 are accommodated in the connection pieces 25, 26. It is preferablefor one or both of the connection pieces 25, 26 to form a click-fitconnection to the cover 11.

As a result of the subsequent operation of the two pumps 4, 5 with theaid of the operating button 6, the two fluid substances will bedispensed simultaneously with a predetermined volumetric delivery and ina defined volumetric ratio. As a result of the fluid substances havingbeen dispensed from the reservoir by the dispensing unit 1, the twopistons 13, 16 will move back towards the outlet side.

The two pistons 13, 16 are made from a suitable plastic. A plastic ofthis type will generally undergo relaxation, with the result that thesealing lips of the pistons 13, 16 will become ever less resilient overthe course of time, so that the seal formed as they bear against theinner side of the first tube 10 and the outer side of the first tube 10and the inner side of the second tube 14 will deteriorate. Consequently,the pistons may start to leak.

To counteract this effect, in the preferred embodiment shown, thediameter or cross section of the first and/or second reservoir decreasestowards the outlet side at least between the piston position associatedwith a completely filled reservoir and the filling position of thepiston. For this purpose, for the first reservoir 8 the diameter of theinner side of the first cylindrical tube 10 decreases in the directionof the outlet side. For the second reservoir 9, the diameter of theinner side of the second cylindrical tube 14 decreases in the directionof the outlet side while the outer side of the first cylindrical tube 10is designed to be straight. In a variant, this outer side of the firstcylindrical tube 10 may have a diameter which increases in size in thedirection of the outlet side.

As has been described above, the pistons 13, 16 are located in a fillingposition in the vicinity of the outlets 12, 15 prior to the filling ofthe reservoir assembly 3. The pistons 13, 16 of the reservoir assembly 3of a dispensing unit will already be in this filling position afterassembly of the reservoir assembly 3. Often, a reservoir assembly 3 ofthis type will be stored for a certain time before being filled with thefluid substances. To prevent relatively high levels of relaxationoccurring in the material of the pistons 13, 16 during this storage ofthe reservoir assembly 3 as a result of the prestress with which thepistons 13, 16 are arranged in the reservoirs 8, 9 the diameter or crosssection of the first and/or second reservoir 8, 9 is increased at theabovementioned filling position in the vicinity of the outlet.Consequently, the pistons 13, 16 are under a reduced prestress (or evenstress-free) in the abovementioned filling position in the vicinity ofthe outlet, and the abovementioned relaxation will not occur or willscarcely occur.

Therefore, for the preferred embodiment shown, for the first reservoir 8the diameter of the inner side of the first cylindrical tube 10 at theabovementioned filling position substantially corresponds to thediameter of the disk-like piston 13. For the second reservoir 9, thedistance between the outer side of the first cylindrical tube 10 and theinner side of the second cylindrical tube 14 at the abovementionedfilling position in the vicinity of the outlet substantially correspondsto the width of the ring of the annular piston 16. Modifying thereservoirs 8, 9 in this way ensures that the pistons 13, 16 havesufficient resilience to remain leak-free during use even if thereservoir assembly 3 in question is stored for a prolonged period oftime (in the filled or unfilled state).

It can be seen from the figures that the reservoir assembly comprises aconnecting element 17 which, in the vicinity of the ends of the firsttube 10 and the second tube 14 which are remote from the outlet side,connects these tubes 10, 14 to one another. The connecting element 17 isformed integrally with the first cylindrical tube 10. Also, the cover 11and the second cylindrical tube 14 are formed integrally. A number ofopenings 18 are formed in the connecting element 17, so that the space19 between the annular piston 16 and the connecting element 17 is incommunication with the outside air.

The reservoir assembly 3 is therefore formed from two pistons 13, 16 andtwo reservoir elements, namely a first reservoir element which comprisesthe first cylindrical tube 10 and the connecting element 17 and a secondreservoir element which comprises the second cylindrical tube 14 and thecover 11. The two reservoir elements are coupled to one another by afirst snap-action or click-fit connection 20 between the cover and thefirst cylindrical tube 10 and a second snap-action or click-fitconnection 21 between the connecting element 17 and the secondcylindrical tube 14. This results in a very simple structure of thereservoir assembly 3 with the two reservoirs 8 and 9 which alsocomprises all the preferred characteristics described above. Thisstructure comprising two reservoir elements makes an accurate concentricarrangement of the tubes 10 and 14 possible in a form which isadvantageous in terms of production engineering.

According to a preferred embodiment, the filling unit for filling thetwo reservoirs 8, 9 comprises a filling head which is designed to beplaced onto the cover 11 of the reservoir assembly 3 and to fill the tworeservoirs simultaneously through the outlets 12, 15. To be correctlypositioned, the filling head has, for example, a rim which correspondsto the coupling rim 22 and by means of which the filling head is centredon the reservoir assembly 3. The filling head also has two projectingfilling sections which are positioned at least partially in the outlets12, 15 in order to fill the reservoirs 8, 9 and with which the fillinghead is also correctly positioned with respect to the reservoir assembly3.

To fill each reservoir, the filling unit comprises a pump, in particulara plunger pump. In this case, the filling unit is preferably alsoprovided with at least a third pump for sucking out the air in eachreservoir before the reservoirs are filled with the fluid substances.This also prevents air from remaining in the filled reservoir.

FIG. 3 shows a preferred embodiment of a dispensing unit, denotedoverall by reference numeral 101. A dispensing unit 101 of this type isgenerally suitable for holding in the hand and for the simultaneousdispensing of a first and a second fluid substance.

The dispensing unit 101 comprises a reservoir section 102 having a firstreservoir 103 and a second reservoir 104. Furthermore, the dispensingunit comprises a pump assembly 105 having a first pump 106 and a secondpump 107 and a common, manually operable member in the form of anoperating button 108. In the preferred embodiment shown, the pumpassembly 105 can be uncoupled from the reservoir section 102. Theuncoupled pump assembly 105 is shown separately in FIGS. 4 and 5. Theuncoupled reservoir section 102 is shown separately in FIG. 6.

The volumes of the first and second fluid substances dispensed by thefirst pump 106 and/or the second pump 107 per pump operation can beadapted as desired in a simple way, and thus so too can the volumetricratio between the two substances, as will be explained in more detailbelow for the preferred embodiment. It is therefore advantageous thatthe volumetric ratio between the first reservoir 103 and the secondreservoir 104 can be adjusted by, for example, uncoupling the tworeservoirs 103, 104 and replacing them with a combination of reservoirs103′, 104′ whose volumetric ratio corresponds to that in which the fluidsubstances are dispensed. It should be noted that it is also possible toadapt the quantities of fluid substance with which the two reservoirs103, 104 are filled to the volumetric ratio in which the fluidsubstances are dispensed.

The two reservoirs 103, 104 are of the “airless” type, i.e. the fluidsubstance dispensed is not replaced in the reservoir by air, but ratherthe volume of the reservoir is reduced by the volume of the fluidsubstance which has been dispensed. For this purpose, the reservoirs areeach closed off on one side by a follower piston 109 and 110,respectively. Of course, it is also possible to use reservoirs of adifferent type, optionally of the “airless” type. By way of example, itis possible to use a pouch-like reservoir or a reservoir with a fixedvolume, in which case the space which was taken up by the fluidsubstance which has been dispensed is then occupied by outside air.

The first reservoir 103 is formed by the space inside a cylindrical wall111 which forms the side wall of the reservoir 103. At the top side, thereservoir 103 is closed off with the exception of an opening 112 bywhich the reservoir 103 is in communication with the first pump 106. Atthe underside, the reservoir 103 is delimited by the follower piston109. The reservoir is completely filled with the first fluid substance.During the dispensing of this fluid substance, the follower piston 109moves towards the opening 112, reducing the volume of the reservoir. Thedrawing shows the follower piston 109 almost in its topmost position, inwhich the fluid substance present in the reservoir 103 has been almostcompletely dispensed.

The second reservoir 104 is formed by the space inside a secondcylindrical wall 113 but outside the cylindrical wall 111. The secondreservoir 104 is therefore annular and lies concentrically with respectto the first reservoir 103. The second reservoir 104 is also closed offat the top with the exception of an opening 114 for communicationbetween the second reservoir and the second pump 107. At the underside,the second reservoir is delimited by the second follower piston 110. Inthe drawing, the follower piston 110 is also shown in almost its topmostposition.

In the embodiment shown in the drawing, the entire reservoir section isformed by two reservoir elements and the two follower pistons 109, 110.The first reservoir element forms the cylindrical outer wall 113 insidewhich the two reservoirs 103, 104 lie and also the closed top side ofthe two reservoirs 310, 104. The two openings 112, 114 are provided inthis top side in order to allow communication between the reservoirs andthe pumps.

The other reservoir element forms the cylindrical wall 111 which on itsinner side delimits the first reservoir 103 and on its outer sidedelimits the second reservoir 104, and closes off the underside of theannular space between the cylindrical inner wall 111 and the cylindricalouter wall 113 of the reservoir section.

The pump assembly 105 comprises a first pump 106 and a second pump 107for pumping the first and second fluid substances out of the first andsecond reservoirs 103, 104, respectively. The first pump 106 and thesecond pump 107 each have an inlet valve 134 and 135 and each also hasan outlet valve 136 and 137 (FIG. 4). The fluid substances dispensed bythe first pump 106 and the second pump 107 pass into a first outflowpassage 115 and a second outflow passage 116, in which the first andsecond fluid substances flow to the first dispensing opening 117 a andsecond dispensing opening 117 b, respectively.

The outflow passages 115, 116 shown in the diagram are completelyseparate, the dispensing openings 117 a, 117 b of the two outflowpassages being arranged above one another, as can be seen from FIG. 5.It is also possible for the dispensing openings 117 a, 117 b of the twooutflow passages 115, 116 to be designed concentrically or coaxially. Itis also possible for the outflow passages 115, 116 not to be completelyseparate, but rather to be such that they converge sooner, so that thefluid substances come into contact with one another, before the fluidsubstances are dispensed. Depending on the design of the outflowpassages 115, 116 and the properties of the first and second fluidsubstances, the fluid substances will then mix with one another to agreater or lesser extent.

The pump assembly 105 is assembled from a base part 118, a firstexchangeable pump element 119 which forms the pistons of the first pump106 and the second pump 107, and a second exchangeable pump element 120which forms the cylinders of the first pump and the second pump. Thepump assembly 105 also comprises a spring 121.

In the preferred embodiment shown, the first pump 106 and the secondpump 107 are disposed concentrically with respect to one another. Inanother embodiment, it is also possible to use a different arrangementof the pumps 106, 107. By way of example, the two pumps 106, 107 mayalso be disposed next to one another.

The spring 121 is advantageously arranged outside the first and secondpumps. As a result, the fluid substances cannot come into contact withthe spring 121. Furthermore, there is advantageously an invertedU-section 138 provided in the first exchangeable pump element 119, sincethis allows a longer spring to be used in the pump assembly without theheight of the latter having to be increased. A longer spring has theadvantage that the spring exerts a more constant force than a shorterspring of the same type.

The base part 118 has coupling means, in this example a coupling rim122, which is designed to be coupled to the reservoir section by meansof a snap-action connection. For this purpose, the reservoir section isprovided with a corresponding coupling rim 123. The coupling rim 122 isalso provided with a circumferential groove at the outer circumference.If appropriate, a cover (not shown) can be coupled into this groove. Thebase part 118 also has a holding section 124 in which the secondexchangeable pump element 120 is positioned. The holding section 124 isdesigned in such a manner that the second exchangeable pump element 120is centred and if appropriate positioned in this space.

The first exchangeable pump element 119 comprises a first substantiallycylindrical wall 125 for forming the piston of the first pump 106 and asecond substantially cylindrical wall 126 for forming the piston of thesecond pump 107. Furthermore, the first exchangeable pump element 119shown comprises a third substantially cylindrical wall 127 for asnap-action connection for coupling the first exchangeable pump element119 to the operating button 108. A rib is provided on the cylindricalwall 127 for the purpose of this snap-action connection. Furthermore,the first exchangeable pump element 119 also has a substantiallycylindrical wall 128 to which a hook rim 129 is fitted, which is able tocouple with a hook rim 130 on the base part 118.

The second exchangeable pump element 120 comprises a first substantiallycylindrical wall 131 for forming the cylinder of the first pump 106 anda second substantially cylindrical wall 132 for forming the cylinder ofthe second pump 107. The second exchangeable pump element 120 also has athird substantially cylindrical wall 133 which bears against the wall ofthe holding section of the base part 118 for centring and positioningthe second exchangeable pump element 120.

The first exchangeable pump element 119 is coupled to the manuallyoperable operating button 108. As a result of the operating button 108being depressed, the pistons move inside the cylinders of the respectivepumps 106, 107. During the depression of the operating button 108, thefluid substance which is present in the pump is at least partiallypumped through the outflow passages 115, 116 to the dispensing openings117 a, 117 b. When the operating button 108 is released, the spring 121presses the pistons upwards with respect to the cylinders. During thismovement, fluid substance is drawn out of the reservoirs towards thepump chambers between the pistons and cylinders.

The hook rim 130 on the base part 118 and the corresponding hook rim 129on the first exchangeable pump element 119 limit the upward movement ofthe operating button 108 and the first exchangeable pump element 119caused by the spring 121.

The dispensing unit 101 can easily be adapted to dispense the first andsecond fluid substances in different volumetric ratios by exchanging thefirst exchangeable pump element 119 and the second exchangeable pumpelement 120 for different first and second exchangeable pump elements119′, 120′, the surface area of at least one of the pistons of the firstpump 106 or second pump 107 being different, so that in the event of apump stroke a different volume is dispensed by the pump in question andtherefore a different volumetric ratio between the two fluid substancesdispensed is obtained.

1-55. (canceled)
 56. Dispensing unit for dispensing two fluidsubstances, comprising: a pump assembly having a first pump and a secondpump, which can be actuated by two common, manually operable operatingmeans so that they simultaneously dispense the two fluid substances, anda reservoir assembly for holding the two fluid substances, the reservoirassembly comprising two reservoirs, which are each provided with anoutlet at an outlet side and are each delimited by a movable piston onthe side remote from the outlet, which pistons move towards therespective outlets during the dispensing of the fluid substances,characterized in that the reservoir assembly and the pump assembly areseparate assemblies which can be coupled to one another, in such amanner that in the uncoupled state each reservoir can be filled throughthe outlet of the reservoir, after which the pump assembly and thereservoir assembly are coupled to one another.
 57. Dispensing unitaccording to claim 56, wherein each piston prior to filling of therespective reservoir is located in a filling position close to theoutlet.
 58. Dispensing unit according to claim 56, wherein a firstreservoir is delimited by an inner side of a first substantiallycylindrical tube, the reservoir being delimited, on the side remote fromthe outlet side, by a continuous, substantially disk-like piston. 59.Dispensing unit according to claim 56, wherein a second reservoir isdelimited by the outer side of the first cylindrical tube and an innerside of a second substantially cylindrical tube, which surrounds thefirst cylindrical tube, the reservoir being delimited, on the other sidefrom the outlet side, by a continuous, substantially annular piston. 60.Dispensing unit according to claim 56, wherein the diameter or crosssection of the first and/or second reservoir decreases in the directionof the outlet side over at least a section of the length of thereservoir.
 61. Dispensing unit according to claim 60, wherein thediameter of the inner side of the first cylindrical tube decreases inthe direction of the outlet side.
 62. Dispensing unit according to claim60, wherein the distance between the outer side of the first cylindricaltube and the inner side of the second cylindrical tube decreases in thedirection of the outlet side.
 63. Dispensing unit according to claim 60,wherein the diameter of the inner side of the second cylindrical tubedecreases in the direction of the outlet side, the outer side of thefirst cylindrical tube being straight.
 64. Dispensing unit according toclaim 56, wherein the diameter or cross section of the first and/orsecond reservoir is increased at the abovementioned filling position inthe vicinity of the outlet, in such a manner that the piston is under areduced prestress in the abovementioned filling position in the vicinityof the outlet.
 65. Dispensing unit according to claim 64, wherein thediameter of the inner side of the first cylindrical tube, at thelocation of the piston position in the vicinity of the outlet,substantially corresponds to the diameter of the substantially disk-likepiston.
 66. Dispensing unit according to claim 64, wherein the distancebetween the outer side of the first cylindrical tube and the inner sideof the second cylindrical tube, at the location of the piston positionin the vicinity of the outlet, substantially corresponds to the width ofthe ring of the substantially annular piston.
 67. Dispensing unitaccording to claim 56, wherein the reservoir assembly comprises a coverwhich closes off the reservoirs on the outlet side, the first and secondoutlets being arranged in the cover.
 68. Dispensing unit according toclaim 67, wherein the cover is formed integrally with the secondcylindrical tube.
 69. Dispensing unit according to claim 67, wherein thecover comprises a coupling rim for coupling a pump assembly to it inorder to form a dispensing unit.
 70. Dispensing unit according to claim67, wherein the cover is designed to receive a filling head for fillingthe first and second reservoirs.
 71. Dispensing unit according to claim56, wherein the reservoir assembly further comprises a connectingelement which connects the first and second cylindrical tubes to oneanother in the vicinity of those ends of the first and secondcylindrical tubes which are remote from the outlet side.
 72. Dispensingunit according to claim 71, wherein the connecting element is formedintegrally with the first cylindrical tube.
 73. Dispensing unitaccording to claim 67, wherein the cover is connected to the firstand/or second cylindrical tube by means of a click-fit connection. 74.Dispensing unit according to claim 67, wherien the connecting element isconnected to the first and/or second cylindrical tube by means of aclick-fit connection.
 75. Reservoir assembly clearly intended for adispensing unit according to claim
 56. 76. Method for assembling andfilling a reservoir assembly of a dispensing unit according to claim 56,said method comprising the following steps: the assembling of thereservoir assembly, the placing of a filling head of a filling unitwhich is suitable for filling the two reservoirs onto the reservoirassembly, the filling of the first and second reservoirs, during whichstep the first and second reservoirs are filled through the first andsecond outlets, respectively, and the removal of the filling head. 77.Method according to claim 76, wherein each piston, after the reservoirassembly has been assembled, is located in the abovementioned pistonposition in the vicinity of the outlet, the pistons moving from thepiston position in the vicinity of the outlet towards the pistonposition of a completely filled reservoir during the filling operation.78. Method according to claim 76, wherein prior to filling of the firstand/or second reservoir, the air which is present in the first and/orsecond reservoir, respectively, is at least partially sucked out bymeans of the filling unit.
 79. Method according to claim 77, wherein thefirst and second reservoirs are filled simultaneously.
 80. Filling unitfor filling a reservoir assembly according to claim 75, wherein thefilling unit comprises a filling head which is suitable for placing ontothe reservoir assembly and comprises at least two plunger pumps forfilling the first and second reservoirs.
 81. Filling unit according toclaim 79, characterized in that the filling unit also comprises a thirdpump, in particular a plunger pump, for sucking out the air which ispresent in the reservoirs prior to filling the first and secondreservoirs.
 82. Dispensing unit for dispensing a first and a secondfluid substance in a defined (volumetric) ratio, comprising: a first anda second reservoir for a stock of the first and second fluid substances,respectively, a pump assembly, which comprises a first and a second pumpwhich each have a pump chamber with a defined operative volume, and acommon, manually operable operating member for actuating the first andsecond pumps, characterized in that the pump assembly comprises one ormore exchangeable pump elements which form at least part of the firstand/or second pump, so that the operative volume of the pump chamber ofthe first and/or second pump can be adjusted by selection of one or moresuitable exchangeable pump elements and fitting of these elements in thepump assembly.
 83. Dispensing unit according to claim 82, wherein thepump assembly also comprises a base part with a holding section forholding at least one of the exchangeable pump elements.
 84. Dispensingunit according to claim 83, in which the holding section is designed tocentre and/or position the at least one exchangeable pump element. 85.Dispensing unit according to claim 82, wherein the pump assemblycomprises a first exchangeable pump element which is held in the basepart and is coupled to the actuating member.
 86. Dispensing unitaccording to claim 85, wherein the first and/or second pump is a bellowspump, the first exchangeable pump element at least partially forming abellows pump chamber.
 87. Dispensing unit according to claim 82, whereinthe pump assembly comprises, a first and a second exchangeable pumpelement, the first exchangeable pump element being coupled to theoperating member and the second exchangeable pump element being held inthe base part.
 88. Dispensing unit according to claim 87, wherein thefirst and/or second pump is a piston pump, the first exchangeable pumpelement forming the piston of the first or second pump and the secondexchangeable pump element forming the cylinder of the first or secondpump.
 89. Dispensing unit according to claim 88, wherein each pump is apiston pump, and in that the first exchangeable pump element forms bothpistons and the second exchangeable pump element forms both cylinders.90. Dispensing unit according to claim 88, wherein the firstexchangeable pump element comprises a base surface, on which twocylindrical walls are arranged substantially at a right angle in orderto form the pistons, and in that the second exchangeable pump elementcomprises a base plate on which two cylindrical walls are arrangedsubstantially at a right angle in order to form the cylinders. 91.Dispensing unit according to claim 82, wherein the pump assembly isremovably coupled to the first and/or second reservoir.
 92. Dispensingunit according to claim 82, wherein the base part is provided withcoupling means for optionally releasably coupling the pump assembly tothe first and/or second reservoir.
 93. Dispensing unit according toclaim 82, wherein the first reservoir and the second reservoir areformed as a single entity.
 94. Dispensing unit according to claim 82,wherein the first and second pumps are designed coaxially, in particularconcentrically.
 95. Dispensing unit according to claim 82, wherein thereservoirs are designed coaxially, in particular concentrically. 96.Dispensing unit according to claim 82, wherein the first and secondreservoirs are of the “airless” type.
 97. Dispensing unit for dispensingone fluid substance, comprising: at least one reservoir for a stock offluid substance, a pump assembly having at least one pump which has apump chamber with a defined operative volume, and an easy-to-operateoperating means for actuating the at least one pump, wherein the pumpassembly comprises one or more exchangeable pump elements which form atleast a section of the pump, so that the operative volume of the pumpchamber of the pump can be adapted by selecting one or more suitableexchangeable pump elements and by fitting them in the pump assembly. 98.Dispensing unit according to claim 97, wherein the pump assembly alsocomprises a base part having a holding section for holding at least oneof the exchangeable pump elements.
 99. Dispensing unit according toclaim 98 in which the holding part is designed to centre and/or positionthe first exchangeable pump element.
 100. Dispensing unit according toclaim 97, wherein the pump assembly comprises a first exchangeable pumpelement which is held in the base part and is coupled to the actuatingmember.
 101. Dispensing unit according to claim 100, wherein the pump isa bellows pump, the first exchangeable pump element forming a bellowspump chamber.
 102. Dispensing unit according to claim 97, wherein thepump assembly comprises a first and a second exchangeable pump element,the first exchangeable pump element being coupled to the operatingmember and the second exchangeable pump element being held in the basepart.
 103. Dispensing unit according to claim 102, wherein the pump is apiston pump, the first exchangeable pump element forming the piston ofthe pump and the second exchangeable pump element forming the cylinderof the pump.
 104. Pump assembly clearly intended for a dispensing unitaccording to claim
 97. 105. Method for the production of a dispensingunit according to claim 97, in which one or more suitable exchangeablepump elements are selected from a stock of different exchangeable pumpelements as a function of the desired operative volume of the pumpchamber of the first and/or second pump and are fitted in the pumpassembly.